I believe God is good all the time and all good comes from God. I must ask you what you mean by sacrifice. If you mean abandon to become a missionary for God I understand. I would follow whatever God wants me to do from the holy inspirations he sets in my heart.
In today's day and age most people do not hear God. If you tell someone you heard God's voice speaking to you most people would label you with some sort of mental illness.
However I don't ever think God would ever tell someone to murder a person in the name of sacrifice because one of His commandments is "thou shall not kill".
The ultimate sacrifice was Jesus murdered on the cross. Jesus was the most holy sacrifice that God accepted to redeem His sinful children. Since that time there has no longer been a need to create a blood sacrifice for God.
I hope my answer helps you a bit. Cheers :)